HomeMy WebLinkAboutObservation of Excavation 08.03.2022110 � K 8i r�1t6l8s Engineers
Geotechnical and Materials Engineers 5020 County Road 154
and Environmental Scientists Glenwood Springs, CO 81601
phone: (970) 945-7988
t fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Compony www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
August 3, 2022
Louise Marron
P.O. Box 157
Carbondale, Colorado 81623
lamarron421 Ahotmail.com
Project No. 21-7-33 LA
Subject: Observation of Excavation, Proposed Residence, Lot 7, Mountain Springs Ranch,
Mountain Springs Road, Garfield County, Colorado
Dear Louise:
As requested, a representative of Kumar & Associates, Inc. observed the excavation at the
subject site on August 2, 2022 to evaluate the soils exposed for foundation support. The findings
of our observations and recommendations for the foundation design are presented in this report.
These services are provided as supplemental to our Professional Services Agreement to you
dated April 4, 2021. We previously conducted a subsoil study for design of foundations at the
site and presented our findings in a report dated June 30, 2021, Project No. 21-7-331.
The proposed residence will be supported on a spread footing foundation bearing on 2 feet of
compacted structural fill. The structural fill will consist of imported CDOT Class 6 Base Course.
At the time of our visit to the site, the foundation excavation had been cut in one level from 2 to
11 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation
consisted of sandy clay with scattered gravel. The clay soil can possess a swell potential when
wetted. No free water was encountered in the excavation and the soils were slightly moist to
moist.
The soil conditions exposed in the excavation are consistent with those previously encountered
on the site. The exposed soils will be compacted and at least two feet of imported structural fill
will be placed to re-establish foundation bearing grade. The proposed design is suitable for
support of spread footings designed for the recommended allowable bearing pressure of
2,000 psf. Loose disturbed soils should be compacted. Structural fill should be placed in thin
lifts and compacted to at least 98% of standard Proctor density at near optimum moisture
content. Structural fill should consist of imported CDOT Class 6 base course. A representative
of the geotechnical engineer should observe the placement of structural fill and test for
compaction. Other recommendations presented in our previous report which are applicable
should also be observed.
The recommendations submitted in this letter are based on our observation of the soils exposed
within the foundation excavation and the previous limited subsurface exploration at the site.
Variations in the subsurface conditions below the excavation could increase the risk of
foundation movement. We should be advised of any variations encountered in the excavation
Louise Marron
August 3, 2022
Page 2
conditions for possible changes to recommendations contained in this letter. Our services do not
include determining the presence, prevention or possibility of mold or other biological
contaminants (MOBC) developing in the future. If the client is concerned about MOBC, then a
professional in this special field of practice should be consulted.
If you have any questions or need further assistance, please call our office.
Sincerely,
Kumar & Associates, Inc.
VO�'��r 1x PIN
James H. Parsons, P.E. b8663
Reviewed by: ly/2
PV6^11
Robert L Duran, P.E.
JHP/kac
Kumar & Associates, Inc.-: Project No. 21-7-331.A